In a printed wire board including a flexible printed wire board, conventional crossover wiring methods as shown in FIG. 3A and B have been widely used. The materials of construction are generally similar to the materials used in, prior art, U.S. Pat. No. 4,287,394 (Hargita et al.). As part of these configurations insulation 5' is printed/formed on a desirable part of a wiring pattern 2, 3, 4. The wiring pattern 2, 3, 4 is printed by etching copper film or conductive paste which has been placed on a flexible or hard substrate 1. A crossover wiring pattern 10 is printed/formed over the insulating layers 6, 7, 8 (collectively 5') which cover a lower wire 2 of the wiring pattern 2, 3, 4. The crossover wiring pattern 10 connects two terminals (end or connecting portions)/wires 3a, 4a/3, 4 of the connected conductive/wiring pattern 2, 3, 4 on the surface of the substrate 1 across the insulation 5' covering the lower wire 2. In order to obtain the good insulation between the lower conductive/wiring pattern (wire) 2 and the crossover conductive/wiring pattern 10 it is necessary to have an insulating film 5' of a relatively thick predetermined thickness. Because the predetermined thickness cannot be obtained by the application of a single insulation layer, the required predetermined thickness of insulation 5' is obtained by repeating the insulation application procedure two to three times stacking the insulation layers 6, 7, 8 on top of each other. This stacking has been performed conveniently and easily by repeating the insulation application procedure using the same pattern mask several times.
But the above conventional crossover technique has problems because a step is formed at the edge of the crossover insulation between the top of the uppermost insulating pattern layer 8, and the surface of the substrate and the surface of the terminals/wires 3a, 4a/3, 4. This step is relatively large. The crossover wiring pattern 10 is printed/formed across this relatively large step. After the conductive/wiring pattern 10 has been printed/formed it is often found to be disconnected at the point where the wiring pattern crosses the step. Or, even if the wiring pattern 10 across the step is not immediately disconnected, the thickness of the crossover conductive/wiring pattern 10 applied across the step is thin and the conductive/wiring pattern 10 crossing the step is often disconnected during handling, and therefore the reliability of the connection across the step has been poor. These problems also appear in the flexible printed circuit boards where the substrate 1 itself is bent often.